(A) FOXO1 phosphorylation in response to apelin stimulation (1 hour at the indicated concentrations) of HUVECs. (B) Time course of FOXO1 phosphorylation in HUVECs treated with apelin. (C) Subcellular localization of FOXO1 in response to apelin stimulation. Scale bar, 5 µm. (D) Apelin-induced FOXO1 phosphorylation in conjunction with inhibition of phosphoinositide 3-kinase by pretreatment with either Wortmannin or LY-294002. (E) Representative immunoblot of FABP4 in HUVECs in response to apelin knockdown (APLN si), FOXO1 knockdown (FOXO1 si), or both. (F) Representative immunoblot for FABP4 expression in isolated skeletal muscle ECs from the indicated mouse strains. *P < 0.05, **P < 0.01, and ††P < 0.01.